The present invention is related to electronics, and more specifically to a multiphase switching regulator control architecture that enforces current sharing.
Electronic circuits are designed to operate off a supply voltage that is typically assumed to be constant. The supply voltage may be provided by a voltage regulator that is designed and intended to supply a constant DC output voltage regardless of changes in load current or input voltage.
One type of voltage regulator, a multiphase buck switching regulator, is often used when the load current is very high. Each switch within the multiphase buck switching regulator carries less current since each phase has its own switch. As a result, less expensive smaller switches, as opposed to one large switch, may be used within the system. Other benefits of multiphase switching systems include lower output voltage ripple and less abrupt input current variation when compared to single-phase regulator systems.
The present invention is directed at providing a multiphase switching regulator control architecture that enforces current sharing and has low on time.
According to one aspect of the invention, current sharing is enforced across all of the phases of the switching regulator control architecture. Current is equalized across each phase helping to ensure that one phase""s current does not drift higher or lower than the other phases current levels.
According to another aspect of the invention, the inductor current level for each phase is sensed. An average current level for all of the phases is also determined. Each phase""s sensed current level is compared to the average current level. When the phase""s sensed current level is not equal to the average current level, the phase""s current level is adjusted. The current level for the phase may be adjusted higher or lower by changing the switch""s on time for the phase.
According to another aspect of the invention, low on times for the switches are capable. The multiphase switching regulator uses voltage mode control helping to ensure low on times.
According to yet another aspect of the invention a method is provided for enforcing current sharing among all of the phases. Each phase""s current level is compared to an average current for all of the phases and if not equal the phase""s current level is adjusted.